What the label lists and what reports show
Finasteride side effects
Finasteride's FDA label: “The most frequently reported adverse reactions were related to sexual function.” FAERS holds 59,983 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is erectile dysfunction (4,195 reports).
- Generic listed
Check it at the source: the finasteride FDA label on DailyMed (effective March 18, 2026, Organon LLC); the FDA FAERS public dashboard.
What does the patient leaflet say about side effects?
From the patient leaflet: What are the possible side effects of PROSCAR?PROSCAR may increase the chance of a more serious form of prostate cancer. The most common side effects of PROSCAR include: trouble getting or keeping an erection (impotence) decrease in sex drive decreased volume of ejaculate ejaculation disorders enlarged or painful breast. You should promptly report to your doctor any changes in your breasts such as lumps, pain or nipple discharge. The following have been reported in general use with PROSCAR and/or finasteride at lower doses: allergic reactions, including rash, itching, hives, and swelling of the lips, tongue, throat, and face rarely, some men may have testicular pain blood in semen trouble getting or keeping an erection that continued after stopping the medication problems with ejaculation that continued after stopping the medication male infertility and/or poor quality of semen. […]
Source: FDA drug label, Organon LLC, effective March 18, 2026 (SPL set 6f988153-fc74-4ca4-b29a-111f750c4a4b), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsThe most frequently reported adverse reactions were related to sexual function.
Table 2: Incidence ≥2% in One or More Treatment Groups Drug-Related Clinical Adverse Experiences in MTOPS
| Adverse Experience | Placebo (N=737) (%) | Doxazosin 4 mg or 8 mg Doxazosin dose was achieved by weekly titration (1 to 2 to 4 to 8… | Finasteride (N=768) (%) | Combination (N=786) (%) |
|---|---|---|---|---|
| Asthenia | 7.1 | 15.7 | 5.3 | 16.8 |
| Headache | 2.3 | 4.1 | 2.0 | 2.3 |
| Hypotension | 0.7 | 3.4 | 1.2 | 1.5 |
| Postural Hypotension | 8.0 | 16.7 | 9.1 | 17.8 |
| Peripheral Edema | 0.9 | 2.6 | 1.3 | 3.3 |
| Dizziness | 8.1 | 17.7 | 7.4 | 23.2 |
| Libido Decreased | 5.7 | 7.0 | 10.0 | 11.6 |
| Somnolence | 1.5 | 3.7 | 1.7 | 3.1 |
| Dyspnea | 0.7 | 2.1 | 0.7 | 1.9 |
| Rhinitis | 0.5 | 1.3 | 1.0 | 2.4 |
| Abnormal Ejaculation | 2.3 | 4.5 | 7.2 | 14.1 |
| Gynecomastia | 0.7 | 1.1 | 2.2 | 1.5 |
| Impotence | 12.2 | 14.4 | 18.5 | 22.6 |
| Sexual Function Abnormal | 0.9 | 2.0 | 2.5 | 3.1 |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
From the label: adverse reactions, continuedThe drug-related adverse reactions, reported in ≥1% in patients treated with PROSCAR and greater than in patients treated with placebo over a 4-year study are: impotence, decreased libido, decreased volume of ejaculate, breast enlargement, breast tenderness and rash ( 6.1 ). To report SUSPECTED ADVERSE REACTIONS, contact Organon LLC, a subsidiary of Organon & Co., at 1-844-674-3200 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. 4-Year Placebo-Controlled Study (PLESS) In PLESS, 1524 patients treated with PROSCAR and 1516 patients treated with placebo were evaluated for safety over a period of 4 years. The most frequently reported adverse reactions were related to sexual function. 3.7% (57 patients) treated with PROSCAR and 2.1% (32 patients) treated with placebo discontinued therapy as a result of adverse reactions related to sexual function, which are the most frequently reported adverse reactions. …
Source: FDA drug label, Organon LLC, effective March 18, 2026 (SPL set 6f988153-fc74-4ca4-b29a-111f750c4a4b), via openFDA; the full label on DailyMed
What do FAERS reports show?
59,983 reports list finasteride among the medicines taken, each a report of something that happened, not proof the medicine caused it; 5,092 are coded as a death and 16,027 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 22 reactions below, 8 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Finasteride: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions